The invention relates to a preferably thermoplastic folded honeycomb and to a process for producing preferably thermoplastic folded honeycombs.
Folded honeycombs of this type (WO 97/03816) are produced continuously from a single layer (a flat body). The hexagonal cells are folded herein after the introduction of cuts and are bridged by covering-layer connecting surfaces. In all known folded honeycombs of this type, first of all cuts which weaken the flat body have to be introduced. It is generally assumed that without cuts, the three-dimensional structures introduced into the layer will be distorted by the folding in such a way that the cells formed thereby become weaker.
The object of the invention is to be able to produce folded honeycombs with a good attachment to the covering layers without the introduction of cuts. The object set is achieved on the basis of the measures of claims 1 and 6 and further developed by further features of the subclaims.
In the invention, the flat body (a material web) is plastically deformed perpendicularly to the material plane and narrowed (folded) in the conveying direction, until the cell walls meet and can be connected. In this way, a honeycomb layer with closed covering layers is formed. The material comes furthermore to lie alternately doubled in the covering-layer planes and ensures thereby a good, flat attachment of all the honeycomb cell walls to both covering layers.